TY - JOUR T1 - PIWI proteins as prognostic markers in non small cell lung cancer JF - European Respiratory Journal JO - Eur Respir J DO - 10.1183/13993003.congress-2015.PA4238 VL - 46 IS - suppl 59 SP - PA4238 AU - Jorge Moisés AU - Alfons Navarro AU - Rut Tejero AU - Nuria Viñolas AU - Anna Cordeiro AU - Ramón M. Marrades AU - Dolors Fuster AU - Oriol Caritg AU - Carmen Muñoz AU - Laureano Molins AU - Josep Ramírez AU - Mariano Monzó Y1 - 2015/09/01 UR - http://erj.ersjournals.com/content/46/suppl_59/PA4238.abstract N2 - PiwiRNA (piRNA) are a recently discovered class of small RNAs which binds to PIWI proteins. Until recently, their expression was believed to be limited to germinal stem cells. However, piRNA expression has now been identified in somatic cells and especially in tumor cells. We aim to explore the relationship between the activation of the piRNA pathway and the prognosis of non-small cell lung carcinoma (NSCLC).Design: We studied prospectively 71 surgically resected NSCLC patients from 2007 to 2011. We assessed the expression of the four PIWI proteins: PIWIL1-4; both in normal and tumor tissue by RT-PCR (frozen tissue) and also by immunohistochemical techniques (FFPE tissue). The expression levels were correlated with patient outcome: disease free survival (DFS) and the overall survival (OS).Results: The quantification of the mRNA levels of the four PIWI proteins showed first that PIWIL1 where not expressed in any normal tissue, but its expression was detected in 11 tumor samples. Interestingly, the prognosis analysis showed that the 11 patients expressing PIWIL1 had worse DFS (20 vs 50 months; p=0.0078) and shorter OS (32 vs 61 months; p=0.0076). These results were validated by immunochemistry, with a faintly cytoplasmic reactivity in the positive cases. Second, PIWIL3 were not expressed neither in normal lung tissue nor tumor tissue. Third, PIWIL2 and PIWIL4 were detected in all the samples. However, both were downregulated in tumor tissue in comparison to the paired normal tissue (p<0.001). Of note, the patients with lower levels of PIWIL4 had worse prognosis for DFS (28 vs 51 months; p=0.034) and OS (36 vs 62 months;p=0.033).Conclusion: The expression of PIWI 1 and 4 could have prognostic significance in NSCLC. ER -